USRE7499E - Improvement in cuttxng stone and other hard substances - Google Patents

Description

13.6. TILGHMAN.

:UTTING sToNE-AN'D OTHER HARD-SUBSTANCES. No. 7,499. Ressrued Feb. 6, 1877.

@W W @Q15 UNITED STATES PATENT OErIeE.y

` i BENJAMIN o. TILGHMAE, or PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN CUTTiNG STONE AND OTHER HARD SUBSTANCES.

Specilcation forming part of Letters Patent No. 133,501, dated November i6, 1872; reissue No. 79499, dated February 6, 1877; application le December 20, 1876. l

To all 'whom it may concern:

yBe it known that I, BENJAMIN G. 'IILGH- MAN, of Philadelphia, Pennsylvania, have invented certain improvements in Cutting Hard Substances, ot which the following is a speciication: Y

My invention relates to the cutting, sawing, boring, and grinding of stone, giass, pottery, and similarhard substances by means of small grains or globules ot' metal of the nature, character, and mode of action hereinafter more particularly described, rubbed against them under pressure by a saw-blade or other tool in the-same manner as is practiced with sand or emery. v i;

I have discoviered that grains or globules oi' cast-iron of the nature and character hereinafter described possess an efficient cutting or .grinding power on stone, glass, Snc., and on account of the cheapness of this material, and the iacility with which it can, be made into tough and hard grains, I prefer to use it in y practice. I have also discovered that ifa globular or` spheroidal form he given to small grains of iron or steel, or their alloys, their action as a material for sawing, cutting, or grinding stone, glass, &c.,takes place on account of this globularity in a different, and, f believe, more advantageous, manner than when the grains are pointed, sharp, or angular, and that in proportion to the work done less power is required,

v and the wear of tllesaw-blade or rubbingtool The globular grains of metal roll over and over under the rubbing pressure oi' the sawblade or tool, and indent grooves into its soit er material, while they crumble, crush, or pulverize the stone.

The pointed, sharp, or angular grains of metal tend rather to embed `themselves into one of the` rubbing-surfaces and to tear or scratch the other. l

I have also discovered that when iron or steel or their alloys, are subdivided in a melted state, the small grains or globules produced are suitable to be used as alcutting, sawing, and grinding material for stone, glass` 85o. Generally considerable proportions of these grains are othJ globular form, and they canl be produced economicallyin large quantities. l

I have also discovered that whcnrgiron or steel, or their alloys, argi'subdivided into "grains or globules in a meited'state, in suchsaJnanner that the grains becone chill-hardened by rapid cooling, these grains havea greater eficiency as a cutting, sawing, material for stone, glass,

The following is one method ot' carrying my invention into eifect, taking, fori-example, the sawing of marble, sandstone, or granite with grains or globules of ca st-iron made from melted metal and chillhardened, and the kind of saws commonly known and used for sawing stone:

rEhe grains are to be appliedto the saw in the same manner as the sand commonly used, and are fed into the saw-kert' with small streams of water in the same Way. so that a constant supply of them will be washed down, and will he caught and rubbed between the edge of the saw and the stone. The grains which es'cape from the kerf are collected and thrown back again to feed the saw. The supply of water should be sniiicicnt to wash away the mud produced. The small pieces andpowder ofthe worn and broken grains oi metal may be separated from the mineral portion of the mudby known processes of washing, and may be si'ted and reused for such grinding or polishing purposes as their size will suit, or they may be remelted. v Magnets may be used to help the saving.;` and separation of the iron from the mineral powder in a way which is well understood..` v The iron `grains, when suffered to remain in a damp state exposed to the air, are liable to rust and cement together, so as to form solid lumps or crusts, and I have discovered that if the water used on the saws is kept alkaline by lime or other alkali, the iron grains will be less apt to rust and cement together.

The grains can he used with various forms of' reciprocating, circular, crown, or band saws, or with any other suitable known kind of sawinggboring, or rubbing machinery.l Y [n ldrilling holes iu rockswith the metal grains and a rotary drill. I have sometimes usedwt tubular or 'hollow tool', like a crownand Agrinding `case of granite, less saw, which 'will make an annular cut, leaving a-ceutral core to be afterward detached.

When boring a hole without a core, I use a solid tool pierced with a small hole near, but not at, the center.

The'grains can be supplied by means of a stream of water forcibly driven through the central hole, and the mud and metallic fragments escape with the water around the outside of the drilltool. By thus forcibly tra-nsporting and feeding the supply of grains by means of a current of water, saw-cuts or boreholes can be made upward, downward, or

horizontal. g v

The known machinery used for the diamond drills and saws may be applied to working with the metallic-grains.

In certain casesa forced current of air may be used, instead of ,water, to transport the 'supply of grains to the cutting-surface, and

to remqfe'the debris and cool the tool.-

To faci1itate the supply and't-he washing away of the dbris of stone and metal, I have found vit'usefuhjwhen the nature of the operation permits, to'flcause the tool to draw back from th-work slightly and frequently, and to` strike it with a sliding blow, as is practiced in the ordinary process of sawing stone with sand.

Whensawing stone with sand, 'or other abra sive materials which act chiefly by scratching, 'the wear of the saw-blades is lso rapid that it is 'not found advantageous in practice to notch the blade of the frame-saws. Now, I have' discovered. that when the metallic grains or globules are used, which act chiey by rolling and crushing, the wear of the sawblade, in proportion to the depth ot stone, sawed, is, in the case of marble, less than onehalf as much as when sand is used, and in than one-sixth as much as When sand is used.

In consequence of this 4greater durability of the saw-blades, I find it advantageous, for rapid sawing, to make notches in the blades of frame-saws, soas to assist infeeding the grains to the rubbing-surface, and I prefer to make such notches about one-half inch to one inch/wide, and from four to eight inches'apart.

The greater the speed and pressure of the lrubbing,'the faster will be the cutting; but, as'economy in the consumption of the grains is an object, the pressure should be kept be-4 low that which will too rapidly break or crush them. l

For general sawing, cutting, and grinding purposes, I have lfound grains or globules of about from Mone-hundredth (l) to one-twentieth (2%) of an inch diameter to give good practical results; but I do fine myself thereto, and I'intend to use both smaller and larger sizes wherever suitable.

The size of grains or globules most suitable, in view of the economy of time, power, and expense, will varyaccording to the object de sired and the material operated on, and can not mean to con' si.` 1,4m

only '.be ascertained by surfaces, narrower saw-kerfs, and sharper lines and edges, and operate on' hard stones with less pressure, while large grains, at suitable speed and pressure, cut faster into soft stone, make a wide saw-korf, and leave a Arougher surface.

1 have obtained fair average results in sawY ing stone with -roundish grains of about one thirty-fifth to one forty-fifth (Tl-5- of au inch diameter.-

For smoothing and polishing operations I use a series of grains, particles, or powdersof gradually-increasing iineness up to the ulti mate degree, as is practiced in working with sand and emery.

I have found wrought-iron to he a good material for the saws, drills, and other rubbingtools but where more convenient for the pur poseintended, I have also used cast-iron, copper, stone, glass, wood, leather, and the other materials commonly used in the arts for grind.

ing and rubbing with sand and emery. A very hard, close-grained material, like chilled cast-iron or hardened steel, does not answer well, as the grains tend to, slip over it, whereas they ought to partly adhere to or indent them- 1 selves into the surface of the tool or rubber, so as to get sufficient hold o r resistance to enable them, while sinking into the stone, glass, &c., to roll over or scratch into it.

The cutting, boring, sawing, and rubbing tools can be made of shape, so as to produce holes or plane or curved surfaces, or 4any kind of moldings or ornal' mental designs, and the proper rotary, reciprocating, or other movements can be given to the tools and to. the articles operated on by suitable lathes, slide-rests, sawing, planing, boring, or rubbing machines, or other known kinds of machinery; and I do not mean to confine myself to or to claim in this patent any particular form or kind of tool or machine for operating'with the metallic grains.

I have recommended cast-iron as the metal to be generally psed, because tough and hard grains of a -globular form can be made from it cheaply by dividing the state; but I do not confine myself thereto. I have also used grains made in a similar way from steel, and the various mixtures and alloys of iron and steel,with other metals which are known in the arts. Some of these aretougher 4 and harder than cast-iron, but are also more expensive.

Various processes are known in the arts by which melted metals can be divided into small Scattering or atomizing a stream of melted i metal by a jet of steam is another known any suitable size and metalr in a melted y method which l have used to make grains of cast-iron, and li prefer it in practice. The drops of metal should fall into water to cool and harden them.

By operating in a close box or chamber, the atmosphere of which has been deprived of its oxygen, the tendency ofthe drops of hot metal to burn may be prevented.

The grains should be sifted to sizes suitable for their intended use, and, if desired, those of globular shapes may be separated from those of more irregularshapes by rolling them down inclined planes, as is practiced in making lead shot.

Any known process ot' hardening or tempering may be applied to the grains, by which their toughness or hardness may be increased.

Having thus described myinvention, I claim and desire to secure by Letters Patent of the United States- 1. The use of grains or globules made of iron, or cast-iron or steel, or their alloys, subdivided while melted, in the process of cutting, sawing, boring, and grinding stone, glass, pottery, and similar hard substances, substantially as above described.

The use ot' grains or globules made of iron, or cast-iron or steel, or their alloys, subdivided while melted, and of a rounded or spheroidal shape, so as to operate by a rolling crush in the process of cutting, sawing, boring, and grinding stone, glass, pottery, and similar hard substances, substantially as above described.

3. The use of grains or globules made of iron, or cast-iron or steel, or their alloys, and

chill-hardened by cooling from a melted state in the process of cutting, sawing, boring, and grindingstone, glass, pottery, and similar hard substances, substantially as above described.

4. As Aa new -article of manufacture, a cutting, grinding, or abrading material for stone, glass, pottery, and similar hard substances, consisting of grains or globules made oi' iron or cast-iron or steel, or their alloys, subdivided while melted.

5. As a new article of manufacture, a cutting, grinding, or abrading material for stone, glass, pottery, and similar hard substances, consisting of grains or globules made of iron, o1 cast-iron or steel, or their alloys, subdivided while melted, and of a rounded or spheroidal shape, so as to operate byl a rolling crush.

6. As a new article of manufacture, a cutting, grinding, or abrading material for stone, glass, pottery, and similar hard substances, consisting of grains or globules made of iron, or cast-iron or steel, or their alloys, and chilihardened by cooling from a melted state.

7. The use of alkaline water in cutting, sawing, boring,and grinding of stone, glass, pottery, and similar hard substances by grains or globules of iron, or castviron or steel, or theirl alloys.

8. The use of notched `blades for frame-saws in sawing stone and similar hard substances with grains or globules of iron, or cast-iron or steel, or their alloys.

B. o. attent/IAN.

' Witnesses R. A. TILGHMAN, J. BoNsALL TAYLoR.

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